Circuitized substrates such as printed circuit boards and ceramic modules are typically made of organic (e.g., fiberglass-reinforced epoxy resin, also referred to as "FR4") and inorganic (e.g., alumina) materials, respectively. Such structures typically also include layers of internal and/or external wiring, also referred to as power, ground and/or signal planes. These substrates thus serve as mechanical carriers for electronic components, enabling these components to be connected electrically thereto and to each other, if desired.
While initial electronic components only had a relatively few connection terminals (referred to as I/Os, or Input/Output terminals), and only some of these I/O terminals were interconnected, the number and density of the terminals have increased significantly with the rise in level of integration of modern semiconductor components, such as microprocessors or logic chips.
Printed circuit boards and other substrates have been assembled with, on occasion, several (e.g., hundreds) individual components, the applications of these printed circuit boards and substrates ranging from use within consumer electronics to typically larger assemblies such as mainframe computers.
Printed circuit board assemblies are known which include a so-called "work panel" or "work holder" containing several individual boards secured thereto. One example is described in U.S. Pat. No. 5,394,609, assigned to the same assignee as the present invention, wherein a plurality of boards are locked onto a work holder using V-shaped clamps that extend into cooperating apertures in the work holder. In the printed circuit board industry, when manufacturing preliminary products (unpopulated boards) in the format in which these are then supplied to customers (e.g., for component population), it is known to make the work panel frame from the same material used to produce the boards.
Such a work panel therefore comprises a frame or the like structure on which the individual boards are positioned and eventually removed (e.g., once component population has occurred).
As discussed in DE-A-31 13 031, at least one printed circuit board is punched out of a material panel and the remaining part is then used as a carrier for the punched out printed circuit boards, maintaining the arrangement of the remaining part of the material panel and the printed circuit boards during further processing for fitting with components, soldering, etc. One disadvantage of this arrangement is that the material panel is not fully utilized and the work panel frame produced at the same time must be scrapped after component assembly, a costly requirement.
Another method is also known, this involving the use of metal frames to carry the printed circuit boards, e.g., from the equipment stations to soldering stations, etc. This method is, however, also fairly costly, and, significantly, impedes uniform handling and storage due to non-uniform dimensions of such structures.
Printed circuit board assemblies (those having two or more boards) may also be used for multi-purpose applications (work panels) in which all boards function cooperatively to accomplish several purposes. All boards in such an arrangement must obviously function properly. Failure of one board can result in costly repair or replacement operations. It is believed, therefore, that a substrate handling device capable of overcoming the aforementioned and other disadvantages associated with known devices would constitute a significant advancement in the art.